As an input medium, a touch screen provides a better convenience than a keyboard and a mouse. Based on different implementing principles, the touch screen may be classified as a resistance type, a capacitance type, a surface acoustic wave type, an infrared type or the like. Currently, the resistive and capacitive touch screen technique is the most widely used.
Specifically, the capacitive touch screen may include a surface capacitive touch screen, a project self-capacitive touch screen, a project mutual-capacitive touch screen, a single-layer capacitive touch screen and the like. The project mutual-capacitive touch screen is becoming more and more popular due to its advantages such as a high sensitivity and a multi-point touch. A basic principle of the project mutual-capacitive touch screen is as follows. A voltage is added on a driving line, and a signal variation is detected on a detecting line. X-direction coordinates are determined by the driving line, and Y-direction coordinates are determined by the detecting line. In detection, X-direction driving lines are progressively scanned, and in scanning each line of driving lines, a signal on each of the detecting lines is read. Thereby, after one period of scan, an intersection between any one of the lines and any one of the columns may be scanned, and X*Y signals are scanned in total. With this detection method, coordinates of multiple points may be determined, and thus the multi-point touch may be achieved.
As an electronic display product, the project mutual-capacitive touch screen encounters the electrostatic problem, as with other electronic products. In the conventional project mutual-capacitive touch screen, a whole layer of high-resistive membrane material is provided as an electrostatic discharge shielding layer, so as to discharge the electrostatic charges.
However, the high-resistive membrane material has tens of millimeters of delays in the electrostatic discharge due to its high resistance (such as 50M to 100M), thereby the electrostatic charges are not discharged timely and splash screen phenomenon occurs on the project mutual-capacitive touch screen.